anatomy chapter 18

three major portions/divisions of the cardiovascular system

the pump (heart), pipes/plumbing (blood vessels), and the fluid (blood)

functions of blood

transportation, defense, and homeostasis

transportation

blood transports much more than just hormones (ex. nutrients, wastes, oxygen, etc.)

defense

blood, especially shite blood cells, fight off infectious agents as part of the immune system

blood clotting

is vital to preventing loss of too much blood

homeostasis

blood is also used to regulate important aspects such as body temperature, electrolytes (ions such as Na+, Ca++, Cl-, etc.)

Hemostasis

the stopping of a flow of blood

blood can be divided into different components

Plasma (the fluid matrix) and formed elements (the cells)

formed blood elements

red blood cells, white blood cells, platelets

rbc

erythrocyte (red blood cell)

wbc

leukocyte (white blood cell)

platelets

thrombocytes

formed elements take up about

45% of the whole body

separates the formed elements of blood

centrifuge (fast spinning device) separates them

the part of the blood that is formed elements

hematocrit

white coating above the rbc's called

the buffy coat

included in the Buffy coat is

wbc's and platelets (normally less than 1% of blood)

plasma

is made of mostly water, but nutrients, hormones, wastes, etc. also are dissolved in the fluid

plasma is

about half of our blood

the largest blood element

wbc

the smallest blood element

platelets

blood viscosity (thickness)

neither too few rbc's and more than the normal number of rbc's are beneficial

anemia

too few red blood cells

Polycythemia

more than normal number of rbc's

thicker blood is

harder to pump

more blood cells may lead

to more clots (unwanted) forming

blood Ph is very slightly

basic, normally ranging from 7.35-7.45

blood Ph depends upon how large a person is, but is generally about

5 liters (1.25 gallons)

plasma is approximately

92% water, with the majority of the other 8% being plasma proteins

of the plasma proteins (such as antibodies/gamma globulins, hormone transporters, clotting factors [fibrinogen])

the major protein is Albumin

albumin is used to regulate the

osmolarity (concentration) of blood

more albumin can be added if the blood osmolarity drops, or taken out it the osmolarity rises

however these changes are quite gradual (not close to being immediate)

Hemopoiesis

production of blood cells

compared to most other cells of the body

rbcs, wbcs, & platelets have relatively show life spans (a few hours to a few weeks)

plasma is about

46-63% of blood

formed elements is about

37-54% of blood

sites of hemopoiesis

embryonic yolk sac, fetal liver, spleen, lymphatic tissue, & red bone marrow (most of these lose this ability before birth)

stem (and blast) cells are not completely differentiated (mature), while

the suffix cyte (& Phil) refers to mature (differentiated) cells

the two main pathways toward blood cell differentiation/maturation are

myeloid and lymphoid

myeloid

gives to all blood cells, except one

lymphoid

gives rise to one of the five types of wbc's

there are growth factors that will stimulate hemopoiesis but

there are different types used to stimulate production of certain specific formed elements

Erythopoietin

(EPO) stimulates rbc production (secreted from the kidneys & liver)

Thrombopoietin

stimulates platelet production (also from the liver and kidneys)

cytokines

(colony stimulating factors [CSFs]) stimulate wbc production

in erythrocytes nucleus and organelles (ER & mitochondria) are

lost/ejected

biconcave disks

for greater surface area/ exchange across the cell membrane

spectrin

a structural protein that allows rbc's to be flexible (squeeze through capillaries)

hemoglobin

the main molecule for O2 transport and ejecting the nucleus allows for more hemoglobin (more O2 transport)

hemoglobin is made up of

4 folded proteins call globs & 4 hemes (one [Fe] per heme)

2 globins are alpha while 2

are beta chains

Oxyhemoglobin

each heme can pick up an O2 (from the lungs) so potentially a total of 4 O2's can be transported per hemoglobin

deoxyhemoglobin

hemoglobin after it releases oxygen

carbaminohemoglobin

carbon dioxide bound to hemoglobin

Erythrocytes life span is about

120 days, but some are made as others are removed

the iron from the heme is

recycled and stored

the protein portion of the heme is also recycled

eventually becoming bile

bile

a molecule stored in the gallbladder for lipid/fat digestion

even though there are five different types of wbc's and only one type of abc, wbc are considerably

less numerous (almost 100 rbc's for every wbc)

wbc are larger than

rbc (about 2x the size)

wbc have shorter

lifespans - minutes to hours (rbc's weeks)

mature abc's are

nucleated (some with multiple lobes of the nucleus)

wbc's can move

on their own

diapedesis/extravasation (emigration)

moving out of the bloodstream

phagocytosis

moving from place to another (once out of the bloodstream)

chemotaxis

movement of wbc's in response to (positive \= forward) chemicals released by injured/infected cells

all wbc's are phagocytic

meaning they can wrap around cells (and substances) and bring them inside in order to destroy them

granular leukocytes

contains granules - neutrophils, eosinophils, basophils

Neutrophils

main phagocyte, most common, 50-70% of wbc's, polymorphonuclear - multilobed nucleus

Eosinophils

2-4% of wbc's, used against parasitic worms

Basophils

least common

agranular (nongranular) leukocytes

less visible granules - lymphocytes, monocytes

Lymphocytes

20-30% of wbc's (second most abundant)

lymphocytes are subdivided into

B & T cells

some T cells develop into

natural killer cells

when we refer to immunity

we usually are referring to B & T cells

monocytes

2-8% of wbc's

monocytes are the

largest wbc (after fully mature they are called macrophages)

Disorders of Leukocytes

leukopenia, leukemia, lymphoma

Leukopenia

too few leukocytes (lowered immunity)

leukemia

an overabundance of leukocytes due to cancer, but they are not fully mature or functional (so also lowered immunity) - like child "soldiers"

lymphoma

also cancerous; T/B lymphocyte accumulate

platelets are much

smaller than wbc's or rbc's

similar to wbc's, platelets are less

abundant than rbc's (but more platelets than wbc's); about 50 rbc's to one platelet

formed elements abundance most-least

red, platelets, white

Abundance of Leukocytes (Most to least)

neutrophils, lymphocytes, monocytes, eosinophils, basophils

platelets have a shorter

lifespan (10 days) than rbc's

megakaryocyte

cells (very large) that produce platelets

platelet functions are quite varied, but play a major role in

blood hemostaisis (clotting)

Thromobocytosis

too many platelets

thrombopenia

too few platelets (clotting disorders)

all cells have molecules that

stick out of the cell membrane

some of the cells that protrude (stick out of the membrane) are

identification molecules (heart cells have different protrusions than liver cells)

Rbc's have molecules that protrude as well, but

they differ depending on what a person inherits from their parents

the A gene and the B gene are both dominant

but the o gene is recessive

The O gene is recessive, and if genotype OO has protrusions

they are less pronounced

Ao and AA genotypes are both blood type A

while Bo and BB are both blood type B

If someone received both the A and the B genes they are blood type Ab

they are both dominant or co-dominant

someone with the A protrusion (antigen)

does NOT have the A antibody (they have the B antibody)

someone with the B protrusion

does NOT have the B antibody (they have the A antibody)